
body{
    font-size: 20px;
    font-family: 'Times New Roman', Times, serif;
    width: 90%;
    margin: auto;
}


li{
    list-style: none;
}

ul{
    padding: 0;
}

/* 导航栏的设置 */
nav{
    background-color: #eee;
    text-align: center;
    padding: 10px;
}

nav ul li a{
    text-decoration: none;
    color: black;
    margin: auto;
}

nav ul li{
    display: inline;
    list-style: none;
    margin: 10px;
}

/* 主题内容的设置 */
main > *:nth-child(2n){
    background-color: #eee;
}

main > *:nth-child(2n+1){
    background-color: #fff;
}

main >*{
    padding: 30px;
}

section >*{
    margin-left: 30%;
}

p,h1,h2,h3{
    margin-bottom: 0.5em;
    margin-top: 0.5em;
}
